D4 · actual · [S/I]

Spacetime

Three spatial coordinates and temporal location. D4 is spacetime: three spatial coordinates plus one temporal coordinate, locally x, y, z and t. Its metric and causal laws constrain possible histories. The ontology distinguishes one actual history, with events and records, from merely possible modeled alternatives. Four coordinates alone do not establish actuality.

Inherited structure

Relativistic spacetime has four local coordinates with declared metric and causal structure. Physical dynamics remains that of the native sciences.

Claim boundary

A selector can issue a commitment receipt but cannot manufacture the world's outcome receipt. Physical light cones remain bounded by spacetime and c. THE HORN TORUS WAS TESTED AS COSMOLOGY AND FAILED: fitted against the data cosmology uses, it did worse than special relativity, with a best-fit expansion rate of exactly zero. It is kept here as a rapidity illustration and a light-cone diagram, which is what it is good for, and NOT as a cosmological model. The animation shows a real identity; it does not show a surviving theory.

D4 · Spacetime

D4 is spacetime: three spatial coordinates plus one temporal coordinate, locally x, y, z and t. Its metric and causal laws constrain possible histories. The ontology distinguishes one actual history, with events and records, from merely possible modeled alternatives. Four coordinates alone do not establish actuality.

This illustration carries no evidence beyond the typed text above.

Semantic owner: 05_COSMOLOGY/03_FORMAL_SYSTEM/34_D4_D5_CANONICAL_REFERENCE.md

μ4 · candidate crossing (stands)

Verdict source: 48: "μ₁ and μ₄ still stand"

Counterfactual-capacity aperture

Saturation proposal: Actual histories alone do not supply an agent with explicit alternatives, rankings, and conditional plans.
New capability: A finite agent models possible futures, ranks options, coordinates, and selects a reachable action.
Lower-level recovery: Every D5 model token is an actual D4 inscription or process, and every enacted choice returns to D4 consequence.
Evidence: [C] unassessed counterfactual-capacity hypothesis
Prediction: Intervening on represented future content, while holding relevant means fixed, changes present action distributions.
Alternatives: Behavior may be explained by reactive policy, cached control, or lower-level dynamics without a distinct counterfactual capacity.
Kill criterion: If future-content interventions produce no discriminable action change beyond reactive controls, the distinct-capacity claim fails.

Source owner: 05_COSMOLOGY/03_FORMAL_SYSTEM/45_SATURATION_CONTRAST_AND_APERTURE_BOUNDARY.md

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